Intermittent recorder for angle measurement



A. LEPETIT March 31, 1942.

INTERMITTENT RECORDER FOR ANGLE MEASUREMENT Filed March 20, 1939 3 Sheets-Sheet 1 M ME/Wok fl pg/er LEPET/T March31, 1942. A. LEPE-m 2,278,203

INTERMITTENT RECORDER FOR ANGLE MEASUREMENT Q llllallllll flLBERT LEPET/T A. LEPETIT March 31, 1942.

INTERMITTENT RECORDER FOR ANGLE MEASUREMENT Filed Mafch 20,

1959 h 3 Sheets-Sheet 3 nvvexwrog fi'AEEQT LE PET/T Patented Mar. 31, 1942 INTERMITTENT RECORDER FOR ANGLE LIEASUREIVIENT Albert Lepetit, Montrouge, France Application March 20, 1939, Serial No. 262,990 In France May 16, 1938 2 Claims.

The object of the present invention is to provide an optical apparatus for measuring angles for instance altitude such as is performed by a sextant, which permits the recording of the altitude of the star under observation as a function of the time at which said observation is taken.

It also has for its object to trace the average line ticularly as to the recording mechanism, over' the instrument disclosed in my Patent No.

2,106,460, issued January 25, 1938.

My optical apparatus for measuring angles is performed by a sextant, inaccordance with the invention and permitting attainment of the previous objects, presents the characteristics which will appear from the following description and especially from the appended claims.

My optical apparatus, in accordance with the invention, is shown, by way of example, on the accompanying drawings in which:

Fig. 1 shows schematically the optical paths whereby the assembled optical measuring units of my invention function, including both optical and recording units,

Figs. 2 and 3 are two perspective views according to two faces of the apparatus,

Fig-4 is a partial transverse cross-section,

Fig. 5 is a partial cross section,

Fig. 6 is a side view, housing removed, showing the angle measuring device and the time drive for recording,

Figs. '7, 8, 9 are partial transverse cross sections along the lines l7, 8-8, 9-9, respectively of Fig. '6,

Figs. 10 and 11 are similar to Figs. 6 and 9 respectlvely, but shown another position of the elements,

The optical apparatus shown on the enclosed drawings comprises two groups A and B of principal units.

The group A comprises the bubble level i and the device 3 for illuminating said level,

The group 13 comprises two mirrors 6-4 and a lens 8 disposed between said two mirrors.

The mirror 6 is stationary, while the mirror I mounted on a rotatable spindl i is connected to an actuating mechanism with toothed sector 9 and worm l0.

A rotatable element H is graduated, for instance, in tens of degrees, and a dial or circle I2 is graduated in degrees and minutes and also the rotation of mirror I. An intermediate optical system, formed, for example, of two prisms l3-H with total reflection, or of one single double reflection prism, permits passage of the luminous rays from the group A onto the group B. I

To make the observations, the observer puts his eye at 0 and observes the star which lies in the direction of arrow 1 for instance. At the same time, he sets the mirror I by means of the mechanism 9l0--l2, so that the image of the level bubble, successively reflected by the prisms i3 and the mirrors 6-! coincides with that of the star. H

The observer repeats this observation several times for one given star; each time, he makes a mark on a paper or Celluloid sheet 40, fixed to the graduated circle 52 and he reads the graduserves as a knob, permitting the measurement of ll ation on the graduated rotating element ii.

Fig. 2 and the following figures show the way of performing the above operation, but the ele-' ments shown on the diagram of Fig. l are, in accordance with the invention, connected to a reeording device C which records the stars altitudes at the various observations as a function of the times at which said observations are taken.

The entire assembly of angle measuring and recording means is carried by a housing 8 having two main chambers separated by a, wall i9 (Figs. t and 5 of my Patent 2,106,460, and Fig.

of this present application).

One chamber I8 holds the members of group A, viz. the bubble level i, with its illuminating device, the prism 3 and the mirror driving mechanism.

Another chamber I8 contains the optical system of group B, viz. the prism H, the mirror 6, the lens 8 and the rotatable mirror I.

The auxiliary optical system formed by the prisms l3-l4 or one double reflection prism, deviates the luminous beam to bring it in the optical plane 20 of observation (Fig. 5) of the second chamber I 8 the optical transmission from the first to the second chamber is thus insured.

The worm screw mechanism ill and toothed sector 9 operating the orientation of the main mirror I, coacts with, a cylinder (Figs. 2-6-789) which carries a projecting spiral 5| (Figs. 2-6-78-9).

Said cylinder 56, is mounted on a rotating shaft 52, connected through the gears 5354 to the shaft N1 of the worm screw l0 actuating the mirror I. The shaft 52 of the cylinder 50 is carried by a frame 55, movable around the axis X X", which permits adjustable rotation of the whole of cylinder 50 and of its supporting frame 55 in the direction of arrows I or 1 The swivelling.motion of said cylinder 5|! is operated through the button 39 of the needle or pencil I2 recording device, pivoted on a pin 33 carried by a spring blade 34, fixed to the housing I. A fork '35, articulated on the endof a lever 35 is in contact with said pencil 32; the lever 55 swivel mounted around a pivot 31 fixed to the frame It is, in turn, articulated on the end of rod 35 carrying push button 39.

Furthermore, a lever 55, rotatable around a pivot 51 is articulated on the end of the rod 35 at the same point as the lever 35 (Fig. 6).

The opposite end of said lever 55 drives through trunnion 59 and guide 55 a fork 5| which thus slides in the direction of arrows or I (Fig. 6-8) s Said fork 5| carries a swivelling lever 52 having a hook 53 which cooperates with a latch 54 fixed to the frame 55 (Fig. 8). A spring 55 insures the contact between said latch 54 and the hook 53. A recoil spring 55, acting on a prolongation 55 of the frame 55 constantly tends to bring said frame 55 to the position of Fig. 8 i. e. the mid-position.

An escapement mechanism is thus constituted.

A recording ribbon or tape 51, preferably made of coloredvand superficially paraflined paper, is rolled up around a loading reel 55. Said ribbon bears lateral indentations 59 into which the teeth 10 of the two cog-ends Il of take-of! reel 1|, engage; this permits the displacement of the ribbon 51 in the direction of arrow 1'. Said displacement is carried out under the action of a clock mechanism, which is schematically shown at 12 and which rotates the shaft of the take-o3 reel.

This clock mechanism comprises a winding up knob 15 and a stop button 14. I

The ribbon or tape 51 passes between the cylinder ll having a spiral 5| and a plate 15. The

clock mechanism is intended for rolling up the ribbon 51 by a constant length per unit of time, for example 15 millimeters per minute.

I'he ribbon 51 is ruled in rectangles in length and width. In length it is ruled in minutes of time; in width it is ruled in degk'ees of sldereal arc The angular position of the cylinder 55 is determined as a function of the angle by which N vice in such a way that it can be adjusted to permit setting at will, the starting point for the record of altitudes with respect to the ribbon or tape 51, in order to take into account the movement of the star as a function of time. The whole range of recorded altitudes thus remains within the limits of the ribbon width.

Said adjustment is obtained by having the cylinder 50 carrying the spiral 5|, friction mounted on its shaft 52. A mark III permits to bring the cylinder 50 in correct angular position with respect to shaft 52.

'On the other hand, the ribbon or tape 51, as well as the reel 58, the wheels H and the cylinder 50, are protected by a housing 52 jointed at 82 Said housing may be opened to insert the ribbon 51.

A guide blade 84 insures the correct feed of the ribbon or tape 51 after its passage over toothed cogs 1| while a plate 54 is mounted and articulated at 83 so that it can be lowered to permit the disengagement of the ribbon with respect to the teeth of the wheels 1P Thus, the introduction and the disengagement of the ribbon are made easy. In order to slip the ribbon, one presses on the plate 84. The ribbon escapes from the teeth 10 In order to have said ribbon driven by the toothed wheels 1| -1|=, the platellis released. The spring 84 then pushes the plate 54 according to I", said plate 84 then pushing the ribbon 51 which engages through its indentations 59 in the teeth of the wheels H The guide blade 84 is used for cutting that part of the ribbon 51 on which the inscriptions have been made.

The above apparatus may be completed with V an optical system, lighting the level I either by the worm screw III has rotated (i. e. the dial l2) to bring the mirror 1 to a position insuring the coincidence between the image of the star and the image of the level bubble l.

The point of tangency 15 between the spiral II of the cylinder 50 and the ribbon or tape is thus displaced axially according to the direction of arrows f' or I when the cylinder is rotated in one direction or in the other as mirror 1 is alined.

Whenthe spiral 5| tape 51 a dash is marked, the position of which strikes the ribbon or in the direction of arrows f" or I is a function of the angle by which the mirror 1 has rotated.

Thus, an instrument l2 for measuring angular positions is obtained which is connected, on one hand, to a recording device constituted by the cylinder 55 with spiral 5| and, on the other hand, a marker constituted by the paper carried on dial I2, the needle 32 and its operating pushbutton 39.

It is advantageous to mount the recording means of the sun light or through a lamp.

However, in the way of performing the processas described, the apparatus is combined with an optical system 11 having lenses 18-45 with horizontal optical axis. This device which thus permits taking observations on the natural horizon, comprises a sliding system H0 for the setting of the coincidence of the natural horizon and of the level bubble when the dial l2 marks zero.

The operation is the following:

The observer puts in coincidence theimage of the star a and that of the horizon h (Fig. 1) by making the mirror 1 rotate by means of the dial l2. The latter thus rotates by an angle as a function of the star height. There .results a rotation of cylinder 55 and a displacement of the tangency point 15 between the spiral and the ribbon 51 which are also a function of said star height. r

During this operation, the spiral 5| has remained out of contact with'the ribbon 51 (Fig. 8).

The observer then presses on the button." in the direction of arrow 1 (Figs. 6-10), so that the pencil 32 swingsin direction of arrow 1 and traces a line on the paper 40 carried by the dial l2; during said swing of the pencil 32, the spring blade 34 bends so that the pressure of the pencil on the paper 40 remains constant.

Simultaneously, the lever 55 rotates and displaces the fork 5| in direction of arrow 1 (Fig.

The hook 53 of the lever 52 then causes rotation, in the direction of arrow F of the unit formed by the lock '54, the frame 55 and the cylinder 55 about axis 52.

Towards the end of the stroke of push button de- I 35, the latch escapes from the hook 53, so that 2,278,203 the unit l4fl-50 comes rapidly backwards in direction of arrow P under the action of the recoil spring 66. However, said unit goes beyond its position of balance in such a way that the spiral 5| hits the ribbon 61. Said spiral 5! thus traces a dash on said ribbon Cl while the needle 32 traces a line on the paper I. oi the dial ii.

The observer repeats the measurements at various intervals of time, then he eflects a special marking after setting the instrument at the height immediately below the last mark, and he takes note of the sidereal time of the instant.

The observer then stops the clockmovement; then he can cut with the blade the part of the ribbon 61 on which the dashes have been= from each other by a wall, by way of example.

I claim:

1. In a recording device for an angle measuring instrument, a rotatable shalt mounted for precision rotative adjustment for measurement 01' an angle, a rotatable cylinder having a raised spiral circumferential ridge, pivotally mounted radial members ca rying said cylinder at their circumferential extremities, means for driving said cylinder from said shaft, a recording tape, reel means for causing said tape to feed at a determined rate past said cylinder, and manually operable control means comprising recoil spring means actuatable for urging said radial members and said cylinder into marking position to engage said tape and record thereon the setting of said shaft.

2. A recording device according to claim 1, said control means further comprising lever and hook means, latch means engageable with said hook means and normally holding said cylinder out of marking position, and said latch means being mounted when released to cause said recoil spring means to urge said radial members and said cylinder into marking position.

ALBERT LEPE'I'IT. 

